In an email to CFA staff on February 15, from CFA deputy chief officer Steven Warrington, the authority says the state's fleet of ''slip-ons'' and ultra-light tankers had been exhausted and it was planning to use brigade-owned vehicles.

There are two types of CFA vehicles: those directly funded by the CFA and government and those ''owned'' by brigades.

Slip-ons and ultra light tankers are modified utes and 4WDs that can fight fires in hard-to-access terrain.

Mr Warrington's email asked district managers to identify how many brigade-owned lighter vehicles each district had. He also asked them to develop a plan to ensure area coverage would not be compromised ''if/when'' vehicles were deployed outside a district.

''I remind you, but not necessarily your brigades [I will let you handle the sensitivities of our request] that all resources are CFA resources and all CFA resources are for the protection of life and property of all Victorians,'' Mr Warrington wrote.

In September last year the Baillieu government said it was cutting $66 million from the CFA and Metropolitan Fire Brigade budgets but said the cuts would not affect front-line services. The CFA denied the use of brigade-owned vehicles was due to any cost-cutting.

The United Firefighters Union and the state Labor opposition seized on the plan as an example of budget cuts affecting front-line services. The union's national secretary Peter Marshall said the government was failing to invest ''despite inflation, population growth, and extreme weather events''.

''It pretends to be increasing the size of the CFA, but in reality is cutting back on recruiting career firefighters and volunteers, and is scrapping training courses,'' Mr Marshall said.

Emergency Services Minister Peter Ryan's spokesman said the government was spending more than Labor on the CFA. ''This year's budget is the second biggest in CFA history,'' he said.